High Performance A&b Oriented T Zeolite Membrane by a Two-stage Crystallization Synthesis

A thin and dense high-performance T-type zeolite membrane was successfully prepared by a two-step seed crystal induction plus two-step temperature-varied hydrothermal synthesis on inexpensive and macroporous alpha-Al2O3 support. This method can fully perform nucleation of seed crystal, regulate the epitaxial growth and crystal growth direction by changing the hydrothermal crystallization temperature and time during the two-stage. Finally a continuous and defect-free a&b oriented zeolite T membrane was obtained. Effects of crystallization temperature and crystallization time of the first-stage and crystallization temperature of the second-stage on the surface structure and properties of zeolite membranes were investigated. The T-type zeolite membrane prepared under the optimal two-step crystallization condition displayed high pervaporation performance with flux over 3.84 kg.m(-2) h(-1) and separation factor higher than 10000 for separation of 90wt% isopropanol/water at 75 degrees C.